Heterogeneity of Carcinoembryonic Antigen

Summary

DEAE-cellulose chromatography of carcinoembryonic antigen prepared by conventional perchloric acid extraction and affinity chromatography has revealed the presence of several antigenically reactive components. At least eight distinct proteins have been isolated, and preliminary characterization of these will be reported. It appears that most of the components have a similar molecular weight but differ in their overall ionic charge and amino acid composition. As commercial preparations of carcinoembryonic antigen reveal a similar heterogeneity, their significance in the current radioimmunological assay for serum carcinoembryonic antigen levels will be discussed.